Hi,
Buckminster has a headless tool that is capable of configuring itself
from remote update sites (it make use of the Eclipse update manager in a
headless way). Now I'm facing the following problem:

Buckminster has a org.eclipse.buckminster.svn plugin. It is dependent on
the org.tigris.subversion.subclipse.core. Particular care has been taken
not to introduce any UI dependencies in order to keep everything mean
and lean for headless execution. I really appreciate the separation
that's been done in subclipse in this respect.

We also have an org.eclipse.buckminster.svn.headless.feature. It imports
all needed headless eclipse platform plugins and our svn plugin. It also
expresses a requirement on the org.tigris.subversion.subclipse.core
(i.e. it must be installed prior to installing our headless svn
feature). My problem is, using a headless installer, how can I get hold
of that? You don't make a headless feature available and I don't get
passed the point where the installer informs me that I must install all
the UI components before installing your feature.

I see two solutions to this problem:
1. We make the subclipse core plugin available at eclipse.org and
include it in our feature. I'm not sure we can do that. Would Subclipse
allow it? Will Eclipse allow it? Also, doing that would impose the
burden of maintining updates for this plugin. A burden that you already
must carry.
2. You could publish a new feature that only included the headless parts
of subclipse.